JP3169353U - Solar cell and electrode structure thereof - Google Patents

Abstract

A solar cell capable of improving the photoelectric conversion rate and improving the production cost by improving the screen printing technology of twice printing to increase the electrode conductivity and at the same time increasing the reliability and non-defective rate of the solar cell. The electrode structure is provided. An electrode structure of a solar cell is provided on a substrate 10 of a solar cell 1 and includes a plurality of bus bar electrodes 12 and a plurality of comb electrodes 11. The bus bar electrodes 12 are disposed on the substrate 10 with a space including a conductive material, and the comb electrodes 11 are disposed so as to connect the adjacent bus bar electrodes 12 with a space including the conductive material. . The bus bar electrode 12 and the comb electrode 11 are formed by screen printing twice. In the first screen printing, the lower part of the comb-shaped electrode 11 is formed, and in the second screen printing, the upper part of the comb-shaped electrode 11 and the bus bar electrode 12 are formed. [Selection] Figure 1

Description

  The present invention relates to an electrode structure, and more particularly to a solar cell and its electrode structure.

  Photovoltaic power generation is a renewable energy technology that is currently focused on development. Photovoltaic power generation has advantages such as no generation of greenhouse gases such as carbon dioxide in the power generation process, and generation of pollution and noise is equal to zero. For this reason, everyone is expecting that the cost reduction of photovoltaic power generation will be realized to the same level as other power generation costs. However, the cost of solar power generation is increased due to problems such as a stand for installing a frame, a transformer, and a solar cell in addition to the solar cell module. Therefore, it can be said that increasing the power generation efficiency of the solar cell and lowering the power generation cost are factors that determine whether or not the solar power generation market can be expanded.

  The application of the screen printing technology can effectively reduce the manufacturing cost and time of the solar cell in manufacturing the electrode structure of the solar cell. Also, in the screen printing technique applied to the manufacture of the electrode structure, the necessary busbar electrode and finger electrode structures are formed by silver paste printing.

  In order to further increase the photoelectric conversion efficiency of the solar cell, it is necessary to consider a method for lowering the shielding rate of the bus bar electrode against the solar incident light. For this reason, the smaller the surface area on the substrate covered by the bus bar electrode, the better. However, in order to conduct a sufficient electron flow rate, a sufficiently large conduction area is required between the electrode and the substrate, and for the first time, the photoelectric conversion efficiency is increased under conditions that do not affect the conductivity of the electrode. be able to. Conventionally, there is a method of printing a bus bar electrode having a narrow width and a height by applying a screen printing technique of twice printing. However, twice-printed screen printing has the same pattern, and an error occurs in the accuracy of the pattern. When the allowable error is exceeded, the width of the bus bar electrode becomes too wide to increase the photoelectric conversion efficiency of the solar cell. In order to reduce the accuracy error, it is necessary to purchase a screen printing device with high accuracy and use a screen film (plate), which both increase the production cost.

  Therefore, the present invention improves the conventional double-print screen printing technology to increase the electrode conductivity, and at the same time, increase the reliability and non-defective rate of the solar cell, thereby increasing the photoelectric conversion rate of the solar cell. The challenge is to reduce production costs.

  In order to solve the above problems, the present invention improves the conventional double-print screen printing technology to increase the electrode conductivity, and at the same time, to improve the reliability and non-defective product rate of the solar cell. It aims at providing the solar cell which raises a conversion rate, and suppresses production cost, and its electrode structure.

  In order to achieve the above object, an electrode structure of a solar cell of the present invention is installed on a substrate of a solar cell and includes a plurality of bus bar electrodes and a plurality of comb electrodes. The bus bar electrodes are disposed on the substrate at an interval by a material including a conductive material. The comb electrodes are arranged so as to connect the adjacent bus bar electrodes with an interval by a material including a conductive material. The bus bar electrode and the comb electrode are formed by screen printing twice. In the first screen printing, the lower part of the comb electrode is formed, and in the second screen printing, the upper part of the comb electrode and the bus bar electrode are formed.

  In order to achieve the above object, the solar cell of the present invention comprises a substrate, a plurality of bus bar electrodes, and a plurality of comb electrodes. The bus bar electrodes are formed by being placed on the substrate with a gap by a material including a conductive material. The comb electrodes are arranged so as to connect the adjacent bus bar electrodes with an interval by a material including a conductive material. The bus bar electrode and the comb electrode are formed by screen printing twice. The first screen printing forms the lower part of the comb-shaped electrode, and the second screen printing forms the upper part of the comb-shaped electrode and the bus bar electrode.

  In the embodiment of the present invention, the material component of the first screen printing is different from the material component of the second screen printing. Preferably, the conductivity of the second screen printing material is higher than the conductivity of the first screen printing material, and more preferably, the first screen printing material has a permeability of the second screen printing material. It is higher than the permeability.

  In an embodiment of the present invention, the first screen printing material component and the second screen printing material component include silver metal particles and glass powder.

  In an embodiment of the present invention, the substrate is an amorphous silicon substrate, a single crystal silicon substrate, a polycrystalline silicon substrate, a gallium arsenide substrate, or the like.

  In an embodiment of the present invention, the substrate is an N-type semiconductor substrate or a P-type semiconductor substrate.

  Thus, the electrode structure of the solar cell provided by the present invention is different in the first-time screen printing pattern and the second-time pattern. In the present invention, lower portions of a plurality of comb-shaped electrodes are first formed in the first screen printing, and after drying and solidifying, the upper portions of the plurality of comb-shaped electrodes and a plurality of bus bars are further formed in the second screen printing. After the electrode is formed, it is similarly dried and solidified. Preferably, the materials used for the first screen printing and the second screen printing are different. In a preferred embodiment of the present invention, the permeability of the first screen printing material is higher than the permeability of the second screen printing material, and the conductivity of the second screen printing material is the first screen printing. By being higher than the conductivity of the material, the lower part of the comb-shaped electrode formed by the first screen printing preferably passes through the anti-reflection layer of the substrate after high-temperature sintering. Further, the upper part of the comb-shaped electrode and the bus bar electrode formed by the second screen printing only contact with the anti-reflection layer of the substrate after high-temperature sintering, and do not transmit it. Therefore, the solar cell of the present invention and the electrode structure thereof are different from the electrode in which the conventional double-printing screen printing technique adopts the method of repeatedly printing the same pattern, and the environmental durability reliability and bus bar of the solar cell product are different. The purpose of increasing the electrical conductivity of the electrode, reducing the cell breakage rate, and increasing the photoelectric conversion rate of the solar cell while simultaneously keeping the production cost low is achieved.

  The solar cell of the present invention and its electrode structure are different from the electrode in which the conventional double printing screen printing technique adopts the method of repeatedly printing the same pattern, and the environmental durability reliability of the solar cell product and the bus bar electrode The conductivity is increased, the cell breakage rate is kept low, the photoelectric conversion rate of the solar cell is raised, and the production cost is kept low.

It is the top view which showed the solar cell of this invention, and its electrode structure. It is the figure which showed the process of the manufacturing method in the electrode structure of the solar cell of this invention. It is the top view which showed the screen plate used for primary screen printing in the solar cell of this invention. It is the top view which showed the screen plate used for secondary screen printing in the solar cell of this invention.

  Hereinafter, a solar cell and an electrode structure thereof according to a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a solar cell 1 of the present invention and its electrode structure. The solar cell 1 includes a substrate 10, a plurality of bus bar electrodes 12, and a plurality of comb electrodes 11. Among these, the solar cell 1 is a silicon solar cell or a thin film solar cell. The substrate 10 is an amorphous silicon substrate, a single crystal silicon substrate, a polycrystalline silicon substrate, a gallium arsenide substrate, or the like, and further, at least one N-type semiconductor layer or at least one P-type semiconductor layer is previously formed thereon ( PN). Preferably, an I-type semiconductor layer (PIN) is further provided between the N-type semiconductor layer and the P-type semiconductor layer. A flat electrode on the other electrode side is provided on the back side of the substrate 10.

  The plurality of bus bar electrodes 12 are formed on the substrate 10 at intervals with a material including a conductive material. The plurality of comb-shaped electrodes 11 are installed so as to connect the adjacent bus bar electrodes 12 at intervals with a material including a conductive material. In a preferred embodiment of the present invention, the material including the conductive material is a silver paste, which is, for example, a mixture including silver metal fine particles, an organic solvent and an organic binder, and glass powder. And the component of glass powder contains oxide powder (for example, lead, bismuth, silicon, etc.).

  The structure of the solar cell 1 disclosed in the present invention has been described above. Then, the manufacturing method of the electrode structure of this solar cell 1 is demonstrated. FIG. 2 is a diagram showing a process of a manufacturing method in the electrode structure of the solar cell of the present invention. This manufacturing method includes steps S21 to S25. Since the electrode structure (a plurality of comb electrodes 11 and a plurality of bus bar electrodes 12) of the solar cell manufactured by this manufacturing method is as described above, it will not be described again below.

  Step S21 provides the substrate 10. The substrate 10 is a semiconductor substrate 10 that has already been preprocessed. In the pretreatment, for example, at least one N-type semiconductor layer or at least one P-type semiconductor layer (PN) is set on the substrate in advance, and preferably between the N-type semiconductor layer and the P-type semiconductor layer. Further comprises an I-type semiconductor layer (PIN).

  Step S22 is referred to as primary screen printing. In this step, the lower part of the plurality of comb-shaped electrodes 11 is formed by forming a material including a conductive material on the substrate 10 at an interval by primary screen printing. This will be described with reference to FIG. Here, in the screen plate 30 used at the time of primary screen printing, the paste-permeable area 31 at the time of printing, that is, an area where a plurality of comb-shaped electrodes 11 are formed.

  In step S23, the volatile solvent in the material is removed by solidifying the lower part of the comb electrode 11 after the primary screen printing. The solidification method achieves this by a heat solidification method or a light solidification method. Light solidification is, for example, ultraviolet light (UV) solidification. In a preferred embodiment of the present invention, when solidifying the electrode 11 using a heat solidification method, that is, after printing is completed, the solvent is removed by directly drying at 100 to 200 ° C. Does not damage the pattern.

  Step S24 is referred to as secondary screen printing. In this step, a material including a conductive material is formed on the substrate 10 at an interval by secondary screen printing, thereby forming the upper portion of the comb-shaped electrode 11 and the plurality of bus bar electrodes 12. This will be described with reference to FIG. Here, in the screen plate 40 used at the time of secondary screen printing, the paste-permeable area 41 at the time of printing, that is, an area where a plurality of bus bar electrodes 12 are formed. Preferably, the primary screen printing material and the secondary screen printing material are different.

  Preferably, the conductivity of the secondary screen printing material is higher than the conductivity of the primary screen printing material. Preferably, the permeability of the primary screen printing material is higher than the permeability of the secondary screen printing material.

  In step S25, the volatile solvent in the material is removed by solidifying the upper part of the comb electrode 11 and the bus bar electrode 12 after the secondary screen printing. The solidification method is achieved by heat solidification or light solidification. Light solidification is, for example, ultraviolet light (UV) solidification. In a preferred embodiment of the present invention, a solidification method similar to that for solidifying the lower part of the comb-shaped electrode 11 is used.

  As described above, the electrode structure of the solar cell provided by the present invention is such that the lower part of the plurality of comb-shaped electrodes is first formed in the primary screen printing, and after drying and solidifying, the second screen printing is performed. After the upper portions of the plurality of comb-shaped electrodes and the plurality of bus bar electrodes are formed, they are similarly dried and solidified. The primary screen printing pattern and the secondary screen printing pattern are different. Preferably, the materials used for primary screen printing and secondary screen printing are different. In a preferred embodiment of the present invention, the permeability of the primary screen printing material is higher than that of the secondary screen printing material, and the conductivity of the secondary screen printing material is greater than the primary screen printing material. By being higher than the conductivity of the printing material, the lower part of the comb-shaped electrode formed by the primary screen printing is preferably transmitted through the anti-reflection layer of the substrate after high-temperature sintering. Further, the upper part of the comb-shaped electrode and the bus bar electrode formed by the secondary screen printing only contact with the anti-reflective layer of the substrate after high-temperature sintering, and do not transmit it. For this reason, the environmental durability reliability of the solar cell product and the conductivity of the bus bar electrode are effectively increased, and the cell breakage rate is kept low. Therefore, the solar cell of the present invention and its electrode structure are different from the electrode in which the conventional double-printing screen printing technique adopts a method of overlapping printing of the same pattern, while simultaneously increasing the photoelectric conversion rate of the solar cell. Achieving the objective of keeping production costs low.

  The embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and there are design changes and the like within a scope not departing from the gist of the present invention. However, it is included in the present invention.

DESCRIPTION OF SYMBOLS 1 Solar cell 10 Board | substrate 11 Comb-type electrode 12 Bus-bar electrode 30,40 Screen plate 31,41 Area which can permeate | transmit paste

Claims (12)

A solar cell electrode structure installed on a solar cell substrate,
A plurality of bus bar electrodes formed on the substrate at an interval by a material including a conductive material; and
Comb electrodes installed so as to connect the adjacent bus bar electrodes at an interval by a material including a conductive material,
The bus bar electrode and the comb electrode are formed by two screen printings, the primary screen printing forms a lower part of the comb electrode, and the secondary screen printing includes an upper part of the comb electrode and An electrode structure of a solar cell, wherein the bus bar electrode is formed.   The electrode structure according to claim 1, wherein a material component of the primary screen printing is different from a material component of the secondary screen printing.   The electrode structure according to claim 2, wherein the conductivity of the secondary screen printing material is higher than the conductivity of the primary screen printing material.   The electrode structure according to claim 2, wherein the permeability of the primary screen printing material is higher than the permeability of the secondary screen printing material.   The electrode structure according to claim 1, wherein the material component of the primary screen printing and the material component of the secondary screen printing include silver metal fine particles and glass powder. A substrate,
A plurality of bus bar electrodes formed on the substrate at an interval by a material including a conductive material; and
Comb electrodes installed so as to connect the adjacent bus bar electrodes at an interval by a material including a conductive material,
The bus bar electrode and the comb electrode are formed by two screen printings, the primary screen printing forms a lower part of the comb electrode, and the secondary screen printing includes an upper part of the comb electrode and A solar cell, wherein the bus bar electrode is formed.   The solar cell according to claim 6, wherein a material component of the primary screen printing is different from a material component of the secondary screen printing.   The solar cell according to claim 7, wherein the conductivity of the secondary screen printing material is higher than the conductivity of the primary screen printing material.   The solar cell according to claim 7, wherein the permeability of the primary screen printing material is higher than the permeability of the secondary screen printing material.   The solar cell according to claim 6, wherein the material component of the primary screen printing and the material component of the secondary screen printing include silver metal fine particles and glass powder.   The solar cell according to claim 6, wherein the substrate is an amorphous silicon substrate, a single crystal silicon substrate, a polycrystalline silicon substrate, or a gallium arsenide substrate.   The solar cell according to claim 6, wherein the substrate is an N-type semiconductor substrate or a P-type semiconductor substrate.

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